[Elecraft] K2 SSB, "Hi Cur" message on PTT

[Doug Heacock]

I dusted off my old K2 recently and decided to try to wire up an electret
mic and give SSB a try--I've had the SSB module since I built the K2 years
ago, but just never used it, because I had no mic at the time.  I've
discovered that when I ground the PTT line with the K2 in LSB or USB mode, I
get the "Hi Cur" message, and my output power goes to well over 15W,
regardless of the setting of the power output control.

I've done some of the voltage checks recommended in the SSB module manual,
but only those for RX mode--I'm a little nervous about trying to measure
voltages in transmit mode, because I don't know how long the PA can take
that kind of current, and I don't want to fritz the final or cause other
problems.  There are some voltage discrepancies associated with U2--pin 5 on
that device is supposed to have 0.6v in RX mode, but I'm seeing more like
2.5v.  Pin 3 of U4--same story.

If anyone out there has any suggestions for where to look for problems, or
how to do further testing, I'm all ears.  I found an old thread in the list
archives that suggested replacing Q3 and/or Q4 on the K2 control board, in
case one of those 2N7000s happened to take a static electricity hit, but I
haven't had a chance to do that yet (don't have any 7000s lying around), and
I'm somewhat hesitant to go down that path because this rig seems to work
just fine in CW mode.

Many thanks, Doug
-- 
Doug Heacock
AA0MS